Fabrication of Sm3+ and Nd3+ co-doped CeO2 thin-film electrolytes by radio frequency magnetron sputtering

Nanocrystalline Sm3+ and Nd3+ co-doped CeO2 thin-film electrolytes with high in-plane electric conductivities have been deposited via radio frequency magnetron sputtering. The results show that with increased RF power or decreased pressure, a reduction in the level of porosity of the film takes place, along with an increased electric conductivity. Maximum electric conductivity of 9 × 10−3 S cm−1 at 500 °C was achieved with optimal sputtering process. It also indicates that with the change of the substrate from single crystal alumina to polycrystalline alumina, the film structure varies from (1 1 1) preferred orientation to random orientation, accompanied by an enhancement in electric conductivity. Compared with alumina substrates, the quartz substrate shows a negative effect on electric conductivity.

► Nanocrystalline Sm and Nd co-doped ceria thin film electrolytes have been obtained.
► Maximum electric conductivity of 9 × 10−3 S cm−1 at 500 °C was achieved under the optimal fabrication parameters.
► Orientation of the crystal in the thin film can be tuned by substrate.
► The electric conductivity does not depend on the film thickness ranging from 1.83 to 9.86 μm.